/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import java.util.Vector;

import wx.xml.xalan.xml.utils.QName;
import wx.xml.xalan.xpath.ExpressionOwner;
import wx.xml.xalan.xpath.XPathVisitor;
import wx.xml.xalan.xpath.operations.Variable;

/**
 * This class visits variable refs in an XPath and collects their QNames.
 */
public class VarNameCollector extends XPathVisitor {
    Vector m_refs = new Vector();

    /**
     * Reset the list for a fresh visitation and collection.
     */
    public void reset() {
        m_refs.removeAllElements(); //.clear();
    }

    /**
     * Get the number of variable references that were collected.
     *
     * @return the size of the list.
     */
    public int getVarCount() {
        return m_refs.size();
    }

    /**
     * Tell if the given qualified name occurs in
     * the list of qualified names collected.
     *
     * @param refName Must be a valid qualified name.
     * @return true if the list contains the qualified name.
     */
    boolean doesOccur(QName refName) {
        return m_refs.contains(refName);
    }

    /**
     * Visit a variable reference.
     *
     * @param owner The owner of the expression, to which the expression can
     *              be reset if rewriting takes place.
     * @param var   The variable reference object.
     * @return true if the sub expressions should be traversed.
     */
    public boolean visitVariableRef(ExpressionOwner owner, Variable var) {
        m_refs.addElement(var.getQName());
        return true;
    }

}

